From: Mohamed Khalfella <mkhalfella@purestorage.com>
To: Eric Dumazet <edumazet@google.com>
Cc: willemjdebruijn <willemdebruijn.kernel@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Willem de Bruijn <willemb@google.com>,
Alexander Duyck <alexanderduyck@fb.com>,
David Howells <dhowells@redhat.com>,
Jesper Dangaard Brouer <brouer@redhat.com>,
Kees Cook <keescook@chromium.org>,
"open list:NETWORKING [GENERAL]" <netdev@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>,
"open list:BPF [MISC]" <bpf@vger.kernel.org>
Subject: Re: [PATCH] skbuff: skb_segment, Update nfrags after calling zero copy functions
Date: Tue, 29 Aug 2023 15:24:18 -0700 [thread overview]
Message-ID: <20230829222418.GB1473980@medusa> (raw)
In-Reply-To: <CANn89iLzOFikw2A8HJJ0zvg1Znw+EnOH2Tm2ghrURkE7NXvQSg@mail.gmail.com>
On 2023-08-29 12:09:15 +0200, Eric Dumazet wrote:
> Another way to test this path for certain (without tcpdump having to race)
> is to add a temporary/debug patch like this one:
>
> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> index a298992060e6efdecb87c7ffc8290eafe330583f..20cc42be5e81cdca567515f2a886af4ada0fbe0a
> 100644
> --- a/net/core/skbuff.c
> +++ b/net/core/skbuff.c
> @@ -1749,7 +1749,8 @@ int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask)
> int i, order, psize, new_frags;
> u32 d_off;
>
> - if (skb_shared(skb) || skb_unclone(skb, gfp_mask))
> + if (skb_shared(skb) ||
> + pskb_expand_head(skb, 0, 0, gfp_mask))
> return -EINVAL;
>
> if (!num_frags)
>
> Note that this might catch other bugs :/
I was not able to make it allocate a new frags by running tcpdump while
reproing the problem. However, I was able to do it with your patch.
next prev parent reply other threads:[~2023-08-29 22:24 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-28 23:32 [PATCH] skbuff: skb_segment, Update nfrags after calling zero copy functions Mohamed Khalfella
2023-08-29 4:18 ` willemjdebruijn
2023-08-29 6:50 ` Mohamed Khalfella
2023-08-29 8:07 ` Eric Dumazet
2023-08-29 9:31 ` Mohamed Khalfella
2023-08-29 10:09 ` Eric Dumazet
2023-08-29 22:24 ` Mohamed Khalfella [this message]
2023-08-30 3:44 ` Eric Dumazet
2023-08-30 23:28 ` [PATCH v2] skbuff: skb_segment, Call zero copy functions before using skbuff frags Mohamed Khalfella
2023-08-31 6:58 ` Eric Dumazet
2023-08-31 7:29 ` Mohamed Khalfella
2023-08-31 7:43 ` Eric Dumazet
2023-08-31 8:17 ` [PATCH v3] " Mohamed Khalfella
2023-08-31 8:47 ` Eric Dumazet
2023-09-01 7:10 ` patchwork-bot+netdevbpf
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